1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a timing controller and an LCD device including the same, which can prevent an image-quality defect due to an abnormal data enable input signal caused by noise such as static electricity.
2. Discussion of the Related Art
Recently, flat panel display devices that can decrease a weight and a volume corresponding to the limitations of cathode ray tubes (CRTs) are being developed. Liquid crystal display (LCD) devices, plasma display panels (PDPs), field emission display (FED) devices, and light emitting display devices are actively being researched as flat type display devices. However, among such flat panel display devices, LCD devices are easily manufactured, have good drivability of drivers, realize a high-quality image, and thus are attracting much attention.
LCD devices control a light transmittance of a liquid crystal layer with an electric field that is applied to the liquid crystal layer in response to a video signal, thereby displaying an image. The LCD devices have a small size, a thin thickness, and low power consumption, and thus are being applied to televisions, portable computers such as notebook computers, monitors, office automation equipment, audio/video equipment, etc.
LCD devices include a gate driver integrated circuit (IC) for driving a plurality of gate lines and a data driver IC for driving a plurality of data lines. As the LCD devices enlarge in size and become higher in resolution, the number of driver ICs increases. However, since the data driver IC is far more expensive than the gate driver IC, various schemes are recently proposed for decreasing the number of data driver ICs.
As technology for decreasing the number of data driver ICs, LCD devices such as Korean Patent Publication No. 10-2010-0060377 (hereinafter referred to as a patent document) have been known.
The patent document increases the number of existing gate lines by two times but decreases half of the existing data lines, and thus decreases the number of existing data driver ICs by half. Accordingly, the patent document discloses a double rate driving (DRD) type LCD device that realizes resolution equal to the existing resolution.
The DRD type LCD device drives n (where n is a natural number equal to or more than two) number of liquid crystal cells, disposed on one horizontal line, with two gate lines and n/2 number of data lines. In the DRD type LCD device, a timing controller malfunctions due to noise such as static electricity to output various control signals at a timing different from that of a normal state, causing an image-quality defect such as an abnormal screen having a flashing state due to data mixing.
The timing controller generates a data enable signal corresponding to the DRD type on the basis of a data enable input signal inputted from an external system. Also, the timing controller maps input data inputted from the external system to be in correspondence with the DRD type, writes the mapped data in an internal line memory according to the data enable input signal, and reads one horizontal data mapped into the line memory to supply the one horizontal data to the data driver IC according to the data enable signal. Furthermore, the timing controller generates and outputs various control signals for driving the data driver IC and the gate driver IC in the DRD type on the basis of the data enable signal.
However, when static electricity is mixed into the data enable input signal inputted from the external system to the timing controller, the timing controller generates the data enable signal according to the data enable input signal with the static electricity mixed there into. For this reason, the data enable signal has abnormal timing, and thus, a timing that reads and writes the line memory deviates from a normal timing, whereby the timing controller cannot write desired data in the line memory or read desired data from the line memory.
Moreover, since the timing controller generates and outputs various control signals for driving the data driver IC and the gate driver IC in the DRD type on the basis of the abnormal data enable signal, an image-quality defect such as an abnormal screen having a flashing state is caused by omission of a display line or data mixing.